What is the purpose of the POP3 and IMAP protocols in email retrieval? How do they differ in their handling of emails on the server?

Here, the distinctions between "connectionless" and "connection-based" protocols are examined.

A common criticism of layered protocols is the apparent overhead of copying at each stage. Is there any way to put a stop to copycats?

In terms of the protocol stack used by the Internet, how many layers are there in total? Is there a list of particular duties that correspond to each level that may be found anywhere?

At what point in time should inquiries into queuing protocols be initiated?

DNS records should be sorted by record type. Each one has to be defined precisely, with illustrative cases and explanations of why they work the way they do. Is it feasible for a web server and an internal mail server to use the same hostname?

Which two of the following are the most convincing arguments in favour of the use of layered protocols?